CVE-2023-27581
github-slug-action vulnerable to arbitrary code execution
github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0and prior to version 4.4.1, this action uses thegithub.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. This can be used to execute code on the GitHub runners and to exfiltrate any secrets one uses in the CI pipeline. A patched action is available in version 4.4.1. No workaround is available.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.8
github-slug-action vulnerable to arbitrary code execution
github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0and prior to version 4.4.1, this action uses thegithub.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. This can be used to execute code on the GitHub runners and to exfiltrate any secrets one uses in the CI pipeline. A patched action is available in version 4.4.1. No workaround is available.
- Record
CVE-2023-27581- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-77
- Updated
- 2026-11-02
EUVDEUVD-2023-0908
8.8
github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0and prior to version 4.4.1, this action uses thegithub.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. This can be used to execute code on the GitHub runners and to exfiltrate any secrets one uses in the CI pipeline. A patched action is available in version 4.4.1. No workaround is available.
- Record
EUVD-2023-0908- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-6q4m-7476-932w
8.8
github-slug-action vulnerable to arbitrary code execution
Impact
This action uses the github.head_ref parameter in an insecure way.
This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. (Note that first-time PR requests will not be run - but the attacker can submit a valid PR before submitting an invalid PR). This can be used to execute code on the GitHub runners (potentially use it for crypto-mining, and waste your resources) and to exfiltrate any secrets you use in the CI pipeline.
Patches
Pass the variable as an environment variable and then use the environment variable instead of substituting it directly.
Patched action is available on tag v4, tag v4.4.1, and any tag beyond.
Workarounds
No workaround is available if impacted, please upgrade the version
ℹ️ v3 and v4 are compatibles.
References
Here is a set of blog posts by Github's security team explaining this issue.
Thanks
Thanks to the team of researchers from Purdue University, who are working on finding vulnerabilities in CI/CD configurations of open-source software. Their tool detected this security vulnerability.
- Record
GHSA-6q4m-7476-932w- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-77
- Updated
- 2026-11-02
NVD
8.8
github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0and prior to version 4.4.1, this action uses thegithub.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. This can be used to execute code on the GitHub runners and to exfiltrate any secrets one uses in the CI pipeline. A patched action is available in version 4.4.1. No workaround is available.
- Record
CVE-2023-27581- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-77
- Updated
- 2026-11-02
OSV
8.8
github-slug-action vulnerable to arbitrary code execution
github-slug-action is a GitHub Action to expose slug value of GitHub environment variables inside of one's GitHub workflow. Starting in version 4.0.0and prior to version 4.4.1, this action uses thegithub.head_ref` parameter in an insecure way. This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. This can be used to execute code on the GitHub runners and to exfiltrate any secrets one uses in the CI pipeline. A patched action is available in version 4.4.1. No workaround is available.
- Record
CVE-2023-27581- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-77
- Updated
- 2026-11-02
OSVGHSA-6q4m-7476-932w
8.8
github-slug-action vulnerable to arbitrary code execution
Impact
This action uses the github.head_ref parameter in an insecure way.
This vulnerability can be triggered by any user on GitHub on any workflow using the action on pull requests. They just need to create a pull request with a branch name, which can contain the attack payload. (Note that first-time PR requests will not be run - but the attacker can submit a valid PR before submitting an invalid PR). This can be used to execute code on the GitHub runners (potentially use it for crypto-mining, and waste your resources) and to exfiltrate any secrets you use in the CI pipeline.
Patches
Pass the variable as an environment variable and then use the environment variable instead of substituting it directly.
Patched action is available on tag v4, tag v4.4.1, and any tag beyond.
Workarounds
No workaround is available if impacted, please upgrade the version
ℹ️ v3 and v4 are compatibles.
References
Here is a set of blog posts by Github's security team explaining this issue.
Thanks
Thanks to the team of researchers from Purdue University, who are working on finding vulnerabilities in CI/CD configurations of open-source software. Their tool detected this security vulnerability.
- Record
GHSA-6q4m-7476-932w- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-77
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
rlespinasse/github-slug-actionGitHub Actions |
4.0.0 up to 4.4.1 | 4.4.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-27581 is a high vulnerability (CVSS 8.8) in Github-slug-action Project Github-slug-action, published March 13, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.58%, the 75th percentile. Fixed in rlespinasse/github-slug-action 4.4.1.
References
github.com/rlespinasse/github-slug-action/security/advisories/GHSA-6q4m-7476-932w
github.com/rlespinasse/github-slug-action/commit/102b1a064a9b145e56556e22b18b19c624538d94
github.com/rlespinasse/github-slug-action/releases/tag/v4.4.1
securitylab.github.com/research/github-actions-untrusted-input
nvd.nist.gov/vuln/detail/CVE-2023-27581
github.com/advisories/GHSA-6q4m-7476-932w
github.com/CVEProject/cvelistV5/tree/main/cves/2023/27xxx/CVE-2023-27581.json
github.com/rlespinasse/github-slug-action